# Species Output Format Sometimes is Not a Species

**URL:** <https://forum.biobakery.org/t/species-output-format-sometimes-is-not-a-species/4774>\
**Category:** MetaPhlAn\
**Created:** [February 9, 2023, 11:00am UTC](https://forum.biobakery.org/t/species-output-format-sometimes-is-not-a-species/4774 "2023-02-09T11:00:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Dario](https://avatars.discourse-cdn.com/v4/letter/d/bc79bd/32.png) [@Dario](https://forum.biobakery.org/u/Dario)\
**Post date:** [February 9, 2023, 11:00am UTC](https://forum.biobakery.org/t/species-output-format-sometimes-is-not-a-species/4774/1 "2023-02-09T11:00:12Z")

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I’m using the version 4 set of tools. When I set the output to be species, not all results are. For example,

`s__Bacteroidaceae_bacterium 2212467 2.02799`

I thought I could split at the underscore to get genus on the left side and species on the right side. But [Bacteroidaceae is actually a family](https://lpsn.dsmz.de/family/bacteroidaceae). Is it a bug? I would expect to always see a genus name after the double underscore.

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**Author:** ![aitor.blancomiguez](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/aitor.blancomiguez/32/86_2.png) [@aitor.blancomiguez](https://forum.biobakery.org/u/aitor.blancomiguez)\
**Post date:** [February 21, 2023, 1:11pm UTC](https://forum.biobakery.org/t/species-output-format-sometimes-is-not-a-species/4774/2 "2023-02-21T13:11:48Z")

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Hi @Dario  
MetaPhlAn 4 taxonomy is based on the NCBI taxonomy of the reference genomes included in our genomic database. In this case, the species you are showing corresponds to the following ncbi taxonomy [Taxonomy browser (Bacteroidaceae bacterium)](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=2212467)